However, Chow said he had not had any information on his application since 3 September when he received an email from visa authorities apologising for the delay but offering no explanation.

An earlier email from the Foreign Office, sent on 27 August, advised Chow his application was still being considered. “There are a number of reasons why we may not be able to meet our processing targets,” it said.

Chow said he believed it was “very likely” his visa had not yet been approved because of his conviction.

In July, he was one of three protest leaders found guilty of unlawfully entering a fenced-off area outside Hong Kong’s government headquarters on 26 September 2014, two days before the umbrella movement began.

Pro-democracy protesters outside the Hong Kong government headquarters during the civil disobedience campaign in September 2014. Photograph: Alex Hofford/EPA

The controversy comes just over a year after British authorities faced criticism when the Chinese artist Ai Weiwei was refused a six-month UK business visa because of a supposed criminal conviction.

The dissident artist disputed such a conviction and said he was being punished for his defence of human rights. Theresa May, then the home secretary, was forced to reverse the decision, granting Ai a business visa and sending him a letter of apology.

Chow also rejected the idea he should be considered a criminal who should not have the right to study in Britain.

“For sure I would not describe myself as a criminal. I would introduce myself as a social activist or a human rights activist,” he said.

“I am pursuing values that the UK supports: democracy, a democratic government, a democratic society, an inclusive open and fair society. This is the goal of the umbrella movement. If you are not [supportive] of defenders who also pursue these kinds of values then are you really upholding these values? I have doubts.”

A Home Office spokesperson said: “We do not routinely comment on individual applications. Each application is considered on its individual merits based on the evidence provided and in line with the immigration rules”.

Chow said: “[The British government portrays itself] as a country which values human rights, democracy and liberty a lot. But, when it comes to advocating human rights, it doesn’t seem as active as they proclaim. If the UK claims it is the friend of human rights [it should not deny activists visas].”